Loose-fill fibrous insulation can be pumped or blown into an attic, wall or wall cavity of a building such as a residential home. Various materials can be added to the fibrous insulation to reduce settling and static discharge, as well as to reduce the amount of dust formed during installation. Conventional systems for forming an insulation product from a loose-fill fibrous insulation, and/or the use of a liquid binder dispersion or water to activate a powdered adhesive, are discussed in U.S. Pat. Nos. 4,710,480, 4,804,695, 5,641,368 and 5,952,418.
Conventional systems for forming an insulation product from loose-fill insulation typically present various disadvantages. For example, conventional systems often suffer from partial or complete blockage of an adhesive nozzle and/or a blowing hose through which the loose-fill insulation is blown. In addition, conventional systems typically employ a relatively high moisture content such as 50% of the dry weight of the preinstalled insulation, to enable proper adhesion between the insulation and the substrate. Such relatively high moisture content can cause mold-related problems such as mold growth on a paper facing of a wallboard. In addition, drying the installed insulation product having a relatively high moisture content can take a relatively long period of time such as two or more days. Such a prolonged drying period can slow down the installation process and contribute to the overall inefficiency thereof.
Conventional systems which use sprayed cellulose loose-fill insulation typically employ a high moisture content to ensure adhesion of the insulation in a cavity. For example, cellulose insulation typically contains water in an amount of 30% to 50% by weight of the insulation. This amount of moisture corresponds to about 2 to 3 pounds of water in the installed insulation per standard eight foot high wall cavity, i.e., a cavity defined by a construction of 8 foot high, nominal 2 by 4 inch framing members (actual 1.5 inch by 3.5 inch) on 16 inch centers. The term “on centers” refers to the distance between the centers of the framing members. This amount of moisture can cause the installation to have a drying time of 2 to 3 days or longer in a dry climatic region such as Denver, Colo. That is, a wallboard typically should be installed after 2 to 3 days or longer to reduce the potential for mold growth. In more humid regions such as Florida, the drying time is typically considerably longer. Longer drying times typically exist when the insulation is installed in a deeper cavity structure.
A dry powdered adhesive can be added to a cellulose insulation material prior to the addition of water to reduce the amount of water used to enable the cellulose to adhere to a wall cavity, as disclosed in U.S. Pat. No. 4,773,960. However, the moisture content of the insulation soon after installation typically remains relatively high, for example, as much as 15% water or more.
Furthermore, cellulose insulation typically has a relatively high moisture storage capacity, which can extend the drying period of the cellulose insulation. ASTM C739 which sets forth the specification for a cellulose loose-fill insulation material, allows a moisture sorption rate as high as 15%. ASTM C764 which sets forth the specification for an inorganic fiber loose-fill material, allows for a moisture sorption rate of only up to 5%.
In addition, it can be difficult to form an insulation product having an acceptable R-value from a loose-fill cellulose material due to the inherent density and thermal characteristics of the cellulose material.
In conventional systems which employ an insulation material having a preinstalled moisture content less than that used in cellulose insulation, the insulation typically does not sufficiently adhere to particular conventional linings of wall cavities causing collapse and lower productivity.
Other systems for installing loose-fill insulation into vertical wall cavities employ a retaining means such as netting or cardboard baffles to retain the loose-fill insulation during blowing. Installing the restraining means typically requires additional labor, for example, as much as an extra day of labor, and can substantially add to the cost of installing the insulation.